We've got method to convert internal value to float, now it's time for next one which I didn't suppose it would be needed but when I was calling to show input screen with previously filled data by then for multiple value characteristic I was always receiving one additional line to these which was passed by me in export parameters. The funny thing was that it wasn't the case when was used. Of course this line was initial but the values were treated after as imputed by user. So as always I started to debug the code to see why it's happening. Finally I found that internal table WS in the function group CTMS was not refreshed during the call of .
As I couldn't refresh it in any call of FM from this function group I had to use old trick with assignment of data from program in memory. But firstly I check with FM if any values are already there.
IT_API_CHAR TYPE TT_API_CHAR